Electrically conducting polymers are of great interest because of potential applications where they may replace metals and semimetals that require comparatively more energy in processing. For example, there is an interest in developing conducting polymers for use, in electronics (Sun et al. "Solution Processable Conducting Polymer: Polyaniline-Polylectrolyte Complexes," Mat. Res. Soc. Symp. Proc., 1994, 328, 209-214; U.S. Pat. No. 5,370,825), as anti-static coatings for fabrics (R. V. Gregory et al. "Electrically Conductive Non-Metallic Textile Coatings," Journal of Coated Fabrics, 1991, 20, 1-9; in corrosion prevention (S. Sathiyanarayanan et al. "Prevention of Corrosion of Iron in Acedic Media Using Poly (o-Methoxy-aniline)," Electrochemica Acta. 1994, 39, 831-837). in photolithography (G. Venungopal et al. "Photoinduced Doping and Photolithography of Methyl-Substituted Polyaniline," Chem. Mater. 1995, 7, 271-276; and in electromagnetic radiation shielding (D. C. Trivedi, S. K. Dhawan, "Shielding of electromagnetic interference using polyaniline," Synthetic Metals, 1993, 267-272.
One of the problems impeding the analysis and development of useful polyconjugated conducting materials is their insolubility in the conducting state. Soluble forms of some polyconjugated polymers are known, but their solubility is usually decreased or lost when the transition is made from the nonconducting to the conducting state. One example of this phenomenon is polyaniline, one of the most highly researched polyconjugated polymers, which shows poor solubility in the conducting state.
Over the past ten years, a considerable effort has been made to prepare novel, water soluble, conducting polymers. For example, U.S. Pat. No. 5,370,825 discloses a water soluble electrically conductive composition of matter comprising a polyacid and a polymer, comprising at least one conjugated region composed of repeating units incorporating a conjugated base atom. Additionally, U.S. Pat. No. 5,422,423 discloses electrically conductive conjugated polymer complexes comprising a substituted or unsubstituted positively charged conjugated polymer, doped with a dopant anion substituted with one or more anionic functionalities, and substituted with one or more hydrogen bonding groups.
Despite the considerable efforts that have been made to discover novel and useful water soluble conducting polymers, there continues to be a need for novel electrically conducting polymers with increased solubility and increased processability. There is also a continuing need for novel electrically conducting polymers that can be prepared from inexpensive materials, and for water soluble conductive polymers that are highly cross-linkable.